Digital Image Correlation is used for controlling load shedding fatigue crack propagation. A specific algorithm is used to perform Stress Intensity Factors (SIFs) and crack length estimation in real time. Crack length measurements are validated by comparison with potential drop technique. SIFs results are compared with more common techniques using standard analytical formula considering confined plasticity at the crack tip. The proposed non-contact method is shown to be a powerful tool to control crack propagation.

A numerical study is presented in this paper to investigate the energy absorption of foam-filled aluminium tubes during crushing. The postbuckling mode of the foam-tube structures has been successfully simulated. The predicted compressive load-displacement is in a good agreement with experimental results. The energy absorption ability of the composite structure due to plastic deformation in a crushing process is evaluated by comparison with the tube structure without foam. The results indicate that the energy absorption of a foam-filled tube structure is superior to the tube without foam. The influences of the friction and the geometric parameters of the structure on the energy absorption have also been investigated. Results from this study will assist automotive industry to design crashworthy components based on foam-filled tubes.

Abstract. The present paper exposes the development of a specific Digital Image Correlation (DIC) method to ensure a fast calculation of fracture parameters such as stress intensity factors and crack length. This measurement is used to control a fatigue crack propagation using the load shedding method in order to ensure a limited plastic damaged crack. The experimental procedure has the main advantage to be fully automotive. The parameters' identification is compared with a more sophisticated identification method and shows a good accuracy.

a b s t r a c tIn order to evaluate the relative contribution of both mechanical and electrochemical processes at the crack tip during Stress Corrosion Cracking propagation, an original combination of controlled pre-cracking followed by thermal pre-oxidation of SCC specimens was developed. It allowed localizing dissolution at the crack tip for Zircaloy-4 tested in halide solutions under potentiostatic polarization. Digital Image Correlation and electrochemical methods were then carried out to study correlations between the stress intensity factor, the crack length and the measurements of dissolution current.